diff --git a/Makefile b/Makefile
index c63d9cd3..59744a49 100644
--- a/Makefile
+++ b/Makefile
@@ -84,7 +84,7 @@ ifeq (${TOOLCHAIN},clang)
   CXXFLAGS_EARLY += -march=native -fPIC
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror -pedantic
   CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized -Wno-unknown-warning-option
-  CXXFLAGS_EARLY += -Wno-invalid-offsetof -Wno-overloaded-virtual
+  CXXFLAGS_EARLY += -Wno-invalid-offsetof
 endif
 
 ifeq (${TOOLCHAIN},gcc)
diff --git a/arbitrile.cpp b/arbitrile.cpp
index 8d434d09..9604883a 100644
--- a/arbitrile.cpp
+++ b/arbitrile.cpp
@@ -807,7 +807,7 @@ struct hrmap_arbi : hrmap {
     return h1;
     }
   
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
     return relative_matrix_recursive(h2, h1);
     }
 
diff --git a/archimedean.cpp b/archimedean.cpp
index 0ca7bf27..4f9fc3ce 100644
--- a/archimedean.cpp
+++ b/archimedean.cpp
@@ -706,7 +706,7 @@ struct hrmap_archimedean : hrmap {
     return calc_relative_matrix(c->cmove(dir), c, C0);
     }
   
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
     if(use_gmatrix && gmatrix0.count(h2->c7) && gmatrix0.count(h1->c7))
       return inverse_shift(gmatrix0[h1->c7], gmatrix0[h2->c7]);
     transmatrix gm = Id, where = Id;
diff --git a/asonov.cpp b/asonov.cpp
index 3ecd0787..0e864e78 100644
--- a/asonov.cpp
+++ b/asonov.cpp
@@ -197,7 +197,7 @@ struct hrmap_asonov : hrmap {
   
   transmatrix adj(heptagon *h, int i) override { return adjmatrix(i); }
   
-  virtual transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
     for(int a=0; a<S7; a++) if(h2 == h1->move(a)) return adjmatrix(a);
     return coord_to_matrix(coords[h2], coords[h1]);
     }
diff --git a/binary-tiling.cpp b/binary-tiling.cpp
index 17107ccd..bccfe8a7 100644
--- a/binary-tiling.cpp
+++ b/binary-tiling.cpp
@@ -453,7 +453,7 @@ EX namespace bt {
       else throw hr_exception("wrong dir");
       }
 
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       if(gmatrix0.count(h2->c7) && gmatrix0.count(h1->c7))
         return inverse_shift(gmatrix0[h1->c7], gmatrix0[h2->c7]);
       transmatrix gm = Id, where = Id;
diff --git a/cell.cpp b/cell.cpp
index 1c2cd0e1..d6ff8e33 100644
--- a/cell.cpp
+++ b/cell.cpp
@@ -30,16 +30,21 @@ struct hrmap {
     printf("create_step called unexpectedly\n"); exit(1);
     return NULL;
     }
-  virtual struct transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) {
-    printf("relative_matrix called unexpectedly\n"); 
+private:
+  virtual transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) {
+    printf("relative_matrixh called unexpectedly\n"); 
     return Id;
     }
-  virtual struct transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) {
-    return relative_matrix(c2->master, c1->master, hint);
+  virtual transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) {
+    return relative_matrixh(c2->master, c1->master, hint);
     }
-  virtual struct transmatrix adj(cell *c, int i) { return adj(c->master, i); }
-  virtual struct transmatrix adj(heptagon *h, int i);
-  struct transmatrix iadj(cell *c, int i) { cell *c1 = c->cmove(i); return adj(c1, c->c.spin(i)); }
+public:
+  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) { return relative_matrixh(h2, h1, hint); }
+  transmatrix relative_matrix(cell *h2, cell *h1, const hyperpoint& hint) { return relative_matrixc(h2, h1, hint); }
+  
+  virtual transmatrix adj(cell *c, int i) { return adj(c->master, i); }
+  virtual transmatrix adj(heptagon *h, int i);
+  transmatrix iadj(cell *c, int i) { cell *c1 = c->cmove(i); return adj(c1, c->c.spin(i)); }
   transmatrix iadj(heptagon *h, int d) { 
     heptagon *h1 = h->cmove(d); return adj(h1, h->c.spin(d));
     }
@@ -94,8 +99,8 @@ struct hrmap {
  **/
 struct hrmap_standard : hrmap {
   void draw_at(cell *at, const shiftmatrix& where) override;
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override;
-  transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override;
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override;
+  transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override;
   heptagon *create_step(heptagon *h, int direction) override;
   transmatrix adj(cell *c, int d) override;
   transmatrix adj(heptagon *h, int d) override;
diff --git a/crystal.cpp b/crystal.cpp
index d0d3c01e..ba3caa2b 100644
--- a/crystal.cpp
+++ b/crystal.cpp
@@ -673,7 +673,7 @@ struct hrmap_crystal : hrmap_standard {
     else hrmap::draw_at(at, where);
     }
 
-  virtual transmatrix relative_matrix(cell *h2, cell *h1, const hyperpoint& hint) override { 
+  transmatrix relative_matrixc(cell *h2, cell *h1, const hyperpoint& hint) override { 
     if(!crystal3()) return hrmap_standard::relative_matrix(h2, h1, hint);
     if(h2 == h1) return Id;
     for(int i=0; i<S7; i++) if(h2 == h1->move(i)) return adj(h1->master, i);
@@ -683,7 +683,7 @@ struct hrmap_crystal : hrmap_standard {
     return xpush(999);
     }
 
-  virtual transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
     if(!crystal3()) return hrmap::relative_matrix(h2, h1, hint);
     return relative_matrix(h2->c7, h1->c7, hint);
     }
diff --git a/euclid.cpp b/euclid.cpp
index 8f147396..ec779512 100644
--- a/euclid.cpp
+++ b/euclid.cpp
@@ -260,7 +260,7 @@ EX namespace euc {
         }
       }
     
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       if(eu.twisted) {
         if(h1 == h2) return Id;
         for(int s=0; s<S7; s++) if(h2 == h1->move(s)) return adj(h1, s);
diff --git a/fake.cpp b/fake.cpp
index 253797e9..c3cbbe19 100644
--- a/fake.cpp
+++ b/fake.cpp
@@ -179,7 +179,7 @@ EX namespace fake {
         }
       }
 
-    transmatrix relative_matrix(cell *h2, cell *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixc(cell *h2, cell *h1, const hyperpoint& hint) override {
       if(arcm::in()) return underlying_map->relative_matrix(h2, h1, hint);
       if(h1 == h2) return Id;
   
@@ -189,7 +189,7 @@ EX namespace fake {
       return Id;
       }
 
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       if(arcm::in()) return underlying_map->relative_matrix(h2, h1, hint);
       return relative_matrix(h2->c7, h1->c7, hint);
       }
diff --git a/geometry2.cpp b/geometry2.cpp
index 49b3f4e0..36c1006e 100644
--- a/geometry2.cpp
+++ b/geometry2.cpp
@@ -120,11 +120,11 @@ EX transmatrix relative_matrix_via_masters(cell *c2, cell *c1, const hyperpoint&
   return gm * U * where;
   }
 
-transmatrix hrmap_standard::relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) {
+transmatrix hrmap_standard::relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) {
   return relative_matrix_via_masters(c2, c1, hint);
   }
 
-transmatrix hrmap_standard::relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) {
+transmatrix hrmap_standard::relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) {
 
   transmatrix gm = Id, where = Id;
   // always add to last!
diff --git a/goldberg.cpp b/goldberg.cpp
index 315b383f..5a2a28b7 100644
--- a/goldberg.cpp
+++ b/goldberg.cpp
@@ -1131,11 +1131,11 @@ EX namespace gp {
       return c;
       }
     
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       return in_underlying([&] { return currentmap->relative_matrix(h2, h1, hint); });
       }
 
-    transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override {
+    transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override {
       c1 = mapping[c1];
       c2 = mapping[c2];
       return in_underlying([&] { return currentmap->relative_matrix(c2, c1, hint); });
diff --git a/kite.cpp b/kite.cpp
index 14d1531c..3bb9f305 100644
--- a/kite.cpp
+++ b/kite.cpp
@@ -326,7 +326,7 @@ struct hrmap_kite : hrmap {
       }
     }
 
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
     if(gmatrix0.count(h2->c7) && gmatrix0.count(h1->c7))
       return inverse_shift(gmatrix0[h1->c7], gmatrix0[h2->c7]);
     transmatrix gm = Id, where = Id;
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index a31d7548..8645fdfa 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -425,7 +425,7 @@ EX namespace sn {
       h->cmove(d); return adjmatrix(d, h->c.spin(d));
       }
     
-    virtual transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
       for(int i=0; i<h1->type; i++) if(h1->move(i) == h2) return adjmatrix(i, h1->c.spin(i));
       if(gmatrix0.count(h2->c7) && gmatrix0.count(h1->c7))
         return inverse_shift(gmatrix0[h1->c7], gmatrix0[h2->c7]);
@@ -943,7 +943,7 @@ EX namespace nilv {
 
     transmatrix adj(heptagon *h, int i) override { return adjmatrix(i); }
   
-    virtual transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override { 
       for(int a=0; a<S7; a++) if(h2 == h1->move(a)) return adjmatrix(a);
       auto p = coords[h1].inverse() * coords[h2];
       for(int a=0; a<3; a++) p[a] = szgmod(p[a], nilperiod[a]);     
@@ -1518,7 +1518,7 @@ EX namespace product {
   int z0;
   
   struct hrmap_product : hybrid::hrmap_hybrid {
-    transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override {
+    transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override {
       return in_underlying([&] { return calc_relative_matrix(where[c2].first, where[c1].first, hint); }) * mscale(Id, cgi.plevel * szgmod(where[c2].second - where[c1].second, hybrid::csteps));
       }
 
@@ -2079,7 +2079,7 @@ EX namespace rots {
       return M = lift_matrix(PIU(currentmap->adj(cw, i)));      
       }
     
-    virtual transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override { 
+    transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override { 
       if(c1 == c2) return Id;
       if(gmatrix0.count(c2) && gmatrix0.count(c1))
         return inverse_shift(gmatrix0[c1], gmatrix0[c2]);
@@ -2087,7 +2087,7 @@ EX namespace rots {
       return Id; // not implemented yet
       }
 
-    virtual transmatrix ray_iadj(cell *c1, int i) override {
+    transmatrix ray_iadj(cell *c1, int i) override {
       if(i == c1->type-1) return uzpush(-cgi.plevel) * spin(-2*cgi.plevel);
       if(i == c1->type-2) return uzpush(+cgi.plevel) * spin(+2*cgi.plevel);
       cell *c2 = c1->cmove(i);
diff --git a/reg3.cpp b/reg3.cpp
index 46e49f95..3778bf6c 100644
--- a/reg3.cpp
+++ b/reg3.cpp
@@ -689,7 +689,7 @@ EX namespace reg3 {
 
     heptagon *getOrigin() override { return allh[0]; }
 
-    transmatrix relative_matrix(cell *h2, cell *h1, const hyperpoint& hint) override;
+    transmatrix relative_matrixc(cell *h2, cell *h1, const hyperpoint& hint) override;
     
     void initialize(int cell_count);
     vector<cell*>& allcells() override { return acells; }
@@ -950,7 +950,7 @@ EX namespace reg3 {
     if(failures && !testing_subconnections) throw hr_exception("hrmap_closed3 failures");
     }
 
-  transmatrix hrmap_closed3::relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) {
+  transmatrix hrmap_closed3::relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) {
     if(c1 == c2) return Id;
     int d = hr::celldistance(c2, c1);
 
@@ -1505,7 +1505,7 @@ EX namespace reg3 {
       return relative_matrix(h->cmove(d), h, C0);
       }
      
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       auto p1 = reg_gmatrix[h1];
       auto p2 = reg_gmatrix[h2];
       transmatrix T = Id;
@@ -1613,7 +1613,7 @@ EX namespace reg3 {
       clearfrom(allh[0]);
       }    
 
-    struct transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       return iso_inverse(locations[h1->fieldval]) * locations[h2->fieldval];
       }
 
@@ -1927,11 +1927,11 @@ EX namespace reg3 {
       return quotient_map->adj(h, d);
       }
      
-    transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+    transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
       return relative_matrix_recursive(h2, h1);
       }
     
-    transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override {
+    transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override {
       if(PURE) return relative_matrix(c2->master, c1->master, hint);
       return relative_matrix_via_masters(c2, c1, hint);
       }
diff --git a/rogueviz/grigorchuk.cpp b/rogueviz/grigorchuk.cpp
index 0b520007..38878370 100644
--- a/rogueviz/grigorchuk.cpp
+++ b/rogueviz/grigorchuk.cpp
@@ -421,13 +421,13 @@ struct hrmap_grigorchuk : hrmap_standard {
       }
     }
   
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
     if(gmatrix0.count(h2->c7) && gmatrix0.count(h1->c7))
       return inverse_shift(gmatrix0[h1->c7], gmatrix0[h2->c7]);
     return Id;
     }
 
-  transmatrix relative_matrix(cell *c2, cell *c1, const struct hyperpoint& hint) override {
+  transmatrix relative_matrixc(cell *c2, cell *c1, const struct hyperpoint& hint) override {
     if(gmatrix0.count(c2) && gmatrix0.count(c1))
       return inverse_shift(gmatrix0[c1], gmatrix0[c2]);
     return Id;
diff --git a/rogueviz/notknot.cpp b/rogueviz/notknot.cpp
index c5fe91b3..ad4d7bf9 100644
--- a/rogueviz/notknot.cpp
+++ b/rogueviz/notknot.cpp
@@ -1103,7 +1103,7 @@ struct hrmap_notknot : hrmap {
     ray::volumetric::enable();
     }
   
-  transmatrix relative_matrix(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
+  transmatrix relative_matrixh(heptagon *h2, heptagon *h1, const hyperpoint& hint) override {
     return Id;
     }
 
diff --git a/sphere.cpp b/sphere.cpp
index 7ed5a9c1..88062a47 100644
--- a/sphere.cpp
+++ b/sphere.cpp
@@ -172,7 +172,7 @@ struct hrmap_spherical : hrmap_standard {
     return Id;
     }
   
-  transmatrix relative_matrix(cell *c2, cell *c1, const hyperpoint& hint) override {
+  transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override {
     transmatrix T = iso_inverse(get_where(c1)) * get_where(c2);
     if(elliptic) fixelliptic(T);
     return T;